The basic solar nebular disk model (SNDM), developed by Russian astronomer Victor Safronov, and was made available in English in the early 1970's. So your answer is B.<span />
Explanation: The prevailing model for planetary acceleration also known as the fractal assembly dating back to 18th century assumes that the solar system is made up of small grains striking each other chaotically into bigger ones, to form planetesimals.
Plastesimals then collide to form planets. This model was proposed by Russian astronomer Victor Safronov and it was further translated in English in 1970s by George Wetherill.
Spongy bone has trabecular which serve as reinforcing plates against a force. The loss of spongy bones causes weakening of the internal support that the compact bone requires and the entire bone breaks.
